Aight, we all know the 302 can kick arse. Problem is, you need to spend a small fortune just to get some of the basics down pat (the intake and heads on the older injected versions suck). For the money you would spend upgrading to ED XR8, plus these mods, I reckon you'd possibly be able to bolt a low boost turbo setup onto the six. Or go totally spastic on a N/A setup. Yes, I love the sound of a V8, if it were a EL/AU I'd say go the 8, but with the EB its my opinion only to stick with the six

5 speed conversion with reco box....1200/1300 (thats with a reco box, less 500 or so for something just 2nd hand)

Diff....figure 600/700

Head....depends on what you want to do. For a decent port with XR6 spec valves and the like, figure 800 or so. There is a guy up here in Qld who has quoted me a port on a AU head pretty cheap, would be good for 360hp or so I think he said....

currently i'm with AAMI, they were wanting $1700 per year for me (rating 5)
i got a quote from just cars and they quoted $1300 for rating 4.
thats for an EF GLi with exhaust, extractors, lowered, full body kit, upgraded brakes, $1500 mags, $1500 stereo.

they only want imobiliser to be fitted for it to be covered for theft.
which is fine by me!!!

The thing you have here is that you already have a base project with mods done to it already.

If you were to buy an EB-D XR8 you would have to get a stock one for insurance purposes. And then when the time is right, spend big $$$ to get it moving right!

I'm 26 and I've waited since I was 18 to get an XR8. I had 6's mainly for that reason. Insurance!
I've had the beast for 2 1/2 years now and am very happy with it. But these things take time and often a lot of cash to maintain and uphold.

Stick with the 6pack for a while. Enjoy what you've done to it and have a further play with it. When you are a bit older and more financial you can afford to look at getting an 8 without the hassles.